TRANSGRESSIVE-REGRESSIVE CYCLES IN LOWER CRETACEOUS STRATA OF THE U.S. EASTERN GULF COASTAL PLAIN

Three major transgressive-regressive cycles (Early to Late Aptian, Late Aptian to Middle Albian and Middle Albian to Early Cenomanian of 7 to 9 million years in duration and 6 depositional sequences of 3 to 11 million years’ duration have been recognized in Cretaceous strata of the U.S. Eastern Gulf Coastal Plain. The depositional sequences are the LKEGR-1 (Lower Cretaceous, Eastern Gulf Region) (132 to 121 Ma), LKEGR-2 (121 to 118 Ma), LKEGR-3 (118 to 114 Ma), LKEGR-4 (114 to 110 Ma), LKEGR-5 (110 to 105 Ma), and LKEGR-6 (105 to 98 Ma) depositional sequences. The LKEGR-1 depositional sequence includes the Hosston Formation (Hauterivian to Aptian Age). The LKEGR-2 depositional sequence, which includes the Sligo Formation (Early Aptian age), and the LKEGR-3 depositional sequence, which includes the Pine Island Shale, “Donovan” sandstone and James Limestone (Aptian Age), constitute the Early to Late Aptian transgressive-regressive cycle. The LKEGR-4 depositional sequence, which includes the Bexar and Rodessa formations (Late Aptian to Early Albian age), and the LKEGR-5 depositional sequence, which includes the Ferry Lake, Mooringsport and Paluxy formations (Early to Middle Albian age), constitute the Late Aptian to Middle Albian transgressive-regressive cycle. The LKEGR-6 depositional sequence, which includes the Andrew and Dantzler formations (Middle Albian to Early Cenomanian age), constitutes the Middle Albian to Early Cenomanian transgressive-regressive cycle. These transgressive-regressive cycles and depositional sequences can be identified, mapped and correlated throughout the region. They are interpreted to be the result of a combination of post-rift tectonics, variations in siliciclastic sediment supply and dispersal systems, and eustasy. These transgressive-regressive cycles and depositional sequences, where integrated with biostratigraphic data, have the potential to be correlated throughout the Gulf of Mexico area and provide a framework for regional and potential global correlation of Lower Cretaceous strata.